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寒武系底部马店组黑色岩系是南华北盆地最重要的海相烃源岩,油气显示丰富。通过分析具有油气显示岩石中流体包裹体的镜下特征、荧光特征、均一温度以及成分,总结了包裹体的类型与期次,进而反演了马店组烃源岩的油气演化历史。结果表明,马店组原生的盐水包裹体和有机包裹体均一温度范围分别为115~300℃和108~220℃,主峰温度值均为185℃;包裹体含有H2S、CO、H2、N2还原性组分,按C_(1-6)/CO_2值关系将包裹体分为CO_2型(C_(1-6)/CO_2=0.08)、高CO_2型(C_(1-6)/CO_2=0.24)、轻烃+CO_2型(C_(1-6)/CO_2=0.43~0.92)和轻烃型(CO_2≈0)。有机包裹体丰度及成分类型变化显示在成岩作用中期、成岩作用晚期和成岩期后构造期先后有3期生排烃过程,其中成岩期后构造期为高成熟生排烃高峰期,时间为早—中三叠世。马店组原生包裹体着重记录了高成熟凝析油—湿气阶段及过成熟干气阶段的油气生成和充注过程,储层的流体包裹体评价结果为工业气层或气显示层;次生包裹体可能记录了抬升剥蚀期间的流体活动过程。盆地内部中新生代沉积区的马店组烃源岩在燕山—喜马拉雅期仍有较好的二次生烃潜力,是值得进一步勘探的有利目标。
The bottom of the Cambrian Mamat Formation black rock series is the most important marine source rock in South China North Basin, rich in oil and gas. By analyzing the microscopic features, fluorescence characteristics, homogenization temperature and composition of fluid inclusions in oil and gas rocks, the type and period of inclusions are summarized, and the oil and gas evolution history of Maodian source rocks is inverted. The results show that the homogenization temperature range of the original brine inclusions and organic inclusions in Madian Formation is 115 ~ 300 ℃ and 108 ~ 220 ℃ respectively, and the main peak temperature is 185 ℃. The inclusions contain H2S, CO, H2 and N2 reducibility (C_ (1-6) /CO_2=0.08) and high CO_2 (C_ (1-6) /CO_2=0.24) according to the relationship of C_ (1-6) / CO_2, Light hydrocarbons + CO_2 type (C_ (1-6) /CO_2=0.43~0.92) and light hydrocarbon type (CO_2≈0). The changes of abundance and composition type of organic inclusions show that there are three stages of hydrocarbon generation and expulsion processes in the middle of diagenesis, late diagenesis and diagenesis, and the tectonic period of diagenesis period is the peak period of high mature hydrocarbon generation and expulsion, which is earlier Middle Triassic. The Maodian Formation primary inclusions recorded the process of oil and gas formation and filling during the highly mature condensate-wet stage and over mature dry stage. The evaluation results of the fluid inclusions in the reservoir are industrial gas layers or gas display layers. The inclusions may record fluid activity during uplift and erosion. The Maodian Formation source rocks in Mesozoic-Cenozoic sedimentary area in the basin still have good secondary hydrocarbon generation potential in Yanshan-Himalayas period, which is a favorable target for further exploration.